1. Field of the Invention
This invention relates to vehicles having expandable room sections, and more particularly to an improved arrangement for providing a flat floor condition when an expandable room section is moved to an extended position relative to the vehicle.
2. Discussion of the Prior Art
In order to increase the available interior space of recreational vehicles or trailers, it is known to provide a slide-out room section integral with the structure of the vehicle or trailer. During transit, the slide-out room section is retracted and stored in the interior of the vehicle or trailer, with the exterior wall of the slide-out room section approximately flush with the exterior of the vehicle or trailer. To use the slide-out room section, the vehicle is first parked and leveled. The slide-out room section is then slid outward from the vehicle to an extended position, increasing the interior space of the vehicle.
In prior art constructions, the floor of the movable slide-out room section is typically supported on the floor of the stationary room section to which the slide-out room section is movably mounted. With this construction, the floor of the slide-out room section is higher than the floor of the stationary room section, which creates a step-up from the stationary floor to the slide-out room section floor when the slide-out room section is in its extended position. This step formed by the differential in floor height is undesirable, inconvenient and can lead to an injury from a person unwarily tripping or stumbling over the step. Besides limiting the mobility of an occupant of the slide-out room section, the step can cause difficulty in furniture placement and detract from the overall aesthetic appearance of the floor.
To address the problems created by the floor height differential discussed above, various slide-out room structures have been proposed which allow the floor of the movable room section to be flush with the floor of the stationary room section when the slide-out room section is in its extended position. One such flat floor slide-out apparatus is disclosed in U.S. Pat. No. 5,491,933, issued Feb. 20, 1996 to Miller et al. In this patent, each of a pair of inner tubes is slidably mounted to one of a pair of outer tubes. The inner tubes are connected to the slide-out room section, and extension of the inner tubes relative to the outer tubes functions to move the slide-out room outwardly relative to the vehicle. Movement of the inner tubes is caused by a gear engaged with a gear track associated with each inner tube. Each outer tube has a ramped recess formed in an upper wall. A roller is mounted to the inner end of each inner tube, and rides along the ramped recess as the inner tube is extended relative to the outer tube. This movement results in the inner tube pivoting about the drive gear, to lower the outer end of the inner tube and to thereby lower the outer end of the slideout room section. This structure is disadvantageous in that substantial stresses and shocks are placed on the drive gear by the weight of the slide-out room section as the inner tube pivots on the drive gear. Further, this construction requires modification to the structure of the outer tube which entails tooling and manufacturing costs.
Another flat floor slide-out arrangement is illustrated in Schneider U.S. patent application Ser. No. 08/823,169, filed Mar. 25, 1997 (Attorney Ref.: 796-00043) now U.S. Pat. No. 5,902,201. The construction illustrated in this patent application employs a notch formed in the inner end of each inner tube, with a gear track extending along the lower end of the inner tube and along the notch. As the drive gear rotates to extend the inner beam outwardly, the drive gear rides along the contour of the gear track provided by the notch, which results in simultaneous extension and downward movement of the inner tube relative to the outer tube to extend and lower the slide-out room section relative to the stationary room section. This construction is generally satisfactory, but again entails modification of the inner tube or beam in order to lower the slide-out room section upon extension.
Still other flat floor slide-out arrangements are disclosed in Schneider U.S. patent application Ser. No. 08/837,047, filed Apr. 11, 1997 (Attorney Ref.: 796-00042) now U.S. Pat. No. 5,984,396. This patent application describes a number of mounting assemblies for providing vertical movement of a slide-out room section relative to an extension member, such as an inner rail member, for moving the slide-out room section between lowered and raised positions when the slide-out room section is moved between extended and retracted positions. The present application improves upon the mounting assemblies set forth in the '047 application.